Photosensitive resin composition and photoresist ink for manufacturing printed wiring boards

ABSTRACT

A photosensitive resin composition developable with water or a diluted alkali solution comprises the following components (A) to (D). That is, the component (A) is a water-soluble photosensitive resin selected from the group consisting of a first resin obtained by introducing a styryl pyridinium group into a polyvinyl alcohol polymer, a second resin obtained by introducing a styryl quinolinium group into the polyvinyl alcohol polymer, and a third resin obtained by adding N-alkylol(meth)acrylamide to the polyvinyl alcohol polymer. The component (B) is a photosensitive prepolymer having a carboxyl group and at least two ethylenically unsaturated groups in molecule. The component (C) is a photopolymerization initiator. The component (D) is water. The photosensitive resin composition will be preferably used as a photoresist ink for manufacturing printed wiring boards.

This is a continuation of U.S. patent application Ser. No. 09/584,492,filed Jun. 1, 2000 which is a divisional of U.S. patent application Ser.No. 09/265,571 (now U.S. Pat. No. 6,136,507), filed on Mar. 10, 1999,the disclosure of which is hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a photosensitive resin compositiondevelopable with water or a diluted alkali aqueous solution, and aphotoresist ink for manufacturing printed wiring boards.

2. Disclosure of the Prior Art

In the past, photoresist inks developable with a diluted alkali aqueoussolution have been used as inks for manufacturing printed wiring boards,screen printing stencils, color-filter pixels and color-filterprotective films, or a photogravure ink. For example, such photoresistinks are disclosed in Japanese Patent Early Publications No. 5-224413and No. 5-241340.

However, these photoresist inks contain various organic solvents suchthat they can be uniformly applied on substrates. The organic solventsare usually evaporated from the photoresist inks during a predrying stepprior to a subsequent exposing step. Therefore, there are problemsinherent in the use of the organic solvents such as a poor workingcondition, environmental pollution and the occurrence of a fire.

SUMMARY OF THE INVENTION

The present invention concerns a photosensitive resin compositiondevelopable with water or a diluted alkali aqueous solution, which iscapable of improving the above problems. The photosensitive resincomposition contains the following components (A) to (D). That is, thecomponent (A) is a water-soluble photosensitive resin selected from thegroup consisting of a first resin obtained by introducing a styrylpyridinium group into a polyvinyl alcohol polymer, a second resinobtained by introducing a styryl quinolinium group into the polyvinylalcohol polymer, and a third resin adding N-alkylol(meth)acrylamide tothe polyvinyl alcohol polymer. The component (B) is a photosensitiveprepolymer having a carboxyl group and at least two ethylenicallyunsaturated groups in molecule. The component (C) is aphotopolymerization initiator. The component (D) is water.

It is preferred that the photosensitive resin composition furthercontains a photopolymerizable ethylenically-unsaturated monomer as thecomponent (E).

It is particularly preferred to use the photosensitive resin compositionof the present invention as a photoresist ink for manufacturing printedwiring boards.

These and still other objects and advantages will become apparent fromthe following detail descriptions of the preferred embodiments andexamples of the invention.

DETAIL DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the present specification, “(meth)acrylic-” means “acrylic-” and“methacrylic-”. For example, (meth)acrylic acid means acrylic acid andmethacrylic acid. In addition, (meth)acrylamide means acrylamide andmethacrylamide.

A photosensitive resin composition of the present invention comprises awater-soluble photosensitive resin (A), photosensitive prepolymer (B),photopolymerization initiator (C) and water (D).

The water-soluble photosensitive resin (A) is selected from the groupconsisting of a water-soluble photosensitive resin (A1) obtained byintroducing a styryl pyridinium group or a styryl quinolinium group intoa polyvinyl alcohol polymer, and a water-soluble photosensitive resin(A2) obtained by adding N-alkylol(meth)acrylamide to the polyvinylalcohol polymer.

As the polyvinyl alcohol polymer used to prepare the photosensitiveresin (A), for example, it is possible to use a polyvinyl alcoholobtained by complete saponification or a partial saponification ofpolyvinyl acetate, or a water-soluble polyvinyl alcohol derivativeobtained by a reaction of —OH group or —OCOCH₃ group of acompletely-saponified or partially-saponified polyvinyl alcohol with anacid-anhydride containing compound, carboxy-group containing compound,epoxy-group containing compound, or an aldehyde-group containingcompound. In addition, it is possible to use a vinyl alcohol copolymerhaving vinyl alcohol units, which is obtained by the completesaponification or the partial saponification of polyvinyl acetate. Asthe copolymer component of vinyl acetate, for example, it is possible touse (meth)acrylic acid, (meth)acrylamide, N-methylol(meth)acrylamide,styrene, ethylene, propylene, maleic anhydride, (meth)acrylonitrile,(meth)acrylic ester.

It is preferred that the polyvinyl alcohol polymer contains 60 mol % ormore of the vinyl alcohol units within its polymerization unit. Inparticular, when using the polyvinyl alcohol polymer containing 80 mol %or more of the vinyl alcohol units, or the polyvinyl alcohol obtained bythe complete saponification of polyvinyl acetate, there is an advantagethat the photosensitive resin composition of the present invention isexcellent in the water-solubility.

The photosensitive resin (A1) can be prepared by a conventional methoddisclosed in, for example, Japanese Patent Early Publication [KOKAI] No.55-23163, No. 55-62905, or No. 56-11906.

Concretely, for example, the photosensitive resin (A1) can be obtainedby adding a formyl styryl pyridinium salt or a formyl styryl quinoliniumsalt to the polyvinyl alcohol polymer according to an acetal reactionapplying an alcoholic —OH group of the polyvinyl alcohol polymer.

The general formula (1) shows a typical structure of an introducedportion of the styryl pyridinium group in the photosensitive resin (A1).The general formula (2) shows a typical structure of an introducedportion of the styryl quinolinium group in the photosensitive resin (A1).

In these formulas (1) and (2), each of R1 and R2 is hydrogen atom, alkylgroup, or aralkyl group, “X⁻” is a conjugate base of an acid, “m” is aninteger of 1˜6, and “n” is 0 or 1.

It is preferred that an introduction rate of the styryl pyridinium groupor the styryl quinolinium group in the photosensitive resin (A1) iswithin a range of 0.3 to 20 mol %, and more preferably 0.5 to 10 mol %,per vinyl alcohol polymerization unit constructing the photosensitiveresin (A1). In the range of 0.3 to 20 mol % of the introduction rate,the photosensitive resin (A1) is good in the water-solubility, and has asuitable photo-bridging capability.

The water-soluble photosensitive resin (A2) can be prepared by aconventional method disclosed in, for example, Japanese PatentPublication [KOKOKU] No. 49-5923, or Japanese Patent Early Publication[KOKAI] No. 62-267302.

Concretely, for example, the photosensitive resin (A2) can be obtainedby an etherification reaction between a polyvinyl alcohol polymer andN-alkylol(meth)acrylamide in the presence of an acid catalyst such asinorganic acid or sulfonic acid derivative in a good solvent of thepolyvinyl alcohol polymer such as water or a N-methyl pyrrolidonesolution, or a suspension of a bad solvent of the polyvinyl alcoholpolymer.

As the N-alkylol(meth)acrylamide, for example, it is possible to useN-methylol(meth)acrylamide, N-ethylol(meth)acrylamide,N-propylol(meth)acrylamide, or N-butylol(meth)acrylamide. TheN-alkylol(meth)acrylamide can be one of these materials or can be acombination of two or more of these materials, if necessary.

It is preferred that an addition ratio of the N-alkylol(meth)acrylamideis within a range of 0.05 to 25 mol %, and more preferably 0.05 to 15mol %, per vinyl alcohol polymerization unit constructing thephotosensitive resin (A2). In the above range of the addition ratio,better water-solubility and photo-curability of the photosensitive resin(A2) can be obtained.

The photosensitive prepolymer (B) is a photosensitive prepolymer havinga carboxyl group and at least two ethylenically unsaturated groups inmolecule. The photosensitive prepolymer is characterized in that aplurality of groups having photopolymerizable ethylenically-unsaturatedgroups branch from a main chain of the prepolymer. Since thephotosensitive prepolymer contains the carboxyl group, it can beswelled, dispersed or dissolved in a diluted alkali aqueous solution.However, when the photosensitive prepolymer is exposed in the presenceof the photopolymerization initiator, the ethylenically unsaturatedgroups of the prepolymer molecules react each other to increase themolecular weight, so that the dispersing property or the solubility tothe diluted alkali aqueous solution lowers.

Therefore, a film made of the photosensitive resin composition of thepresent invention containing the photosensitive prepolymer (B) can beswelled, dispersed or dissolved in the diluted alkali aqueous solutionbefore the exposing step. However, after the film is cured by theexposing step according to photopolymerization, the dispersing propertyor the solubility to the diluted alkali aqueous solution lowers.Therefore, by applying a difference of the solubility of thephotosensitive resin composition to the diluted alkali aqueous solutionbefore and after the exposing step, it is possible to form a desiredpattern of a cured film of the photosensitive resin composition. Thatis, the film of the photosensitive resin composition is selectivelyexposed, and then developed with the diluted alkali aqueous solution.The non-exposed region of the film is washed away to leave the exposedregion of the film, so that the desired pattern of the cured film of thephotosensitive resin composition is obtained.

The cured film of the photosensitive resin composition can be strippedand removed by the use of sodium periodate. Additionally, since thephotosensitive resin composition of the present invention contains thephotosensitive prepolymer (B) having the carboxyl group, the cured filmcan be stripped and removed by the use of an aqueous solution ofalkali-metal hydroxide.

It is preferred that the photosensitive prepolymer (B) itself can form afilm. In the present invention, since the photosensitive resincomposition contains the photosensitive resin (A) and the photosensitiveprepolymer (B), there is an advantage that a predried film of thephotosensitive resin composition is substantially free from surfacetackiness, so that contamination of a phototool artwork with thephotosensitive resin composition can be prevented even when the artworkis directly put on the predried film.

It is preferred that an acid value of the photosensitive prepolymer (B)is within a range of 20 to 300 mgKOH/g, and more preferably 40 to 200mgKOH/g. In this range of acid value, it is possible to shorten thedeveloping time when developing the photosensitive resin compositionwith the diluted alkali aqueous solution. In addition, since theresistance to diluted alkali aqueous solution of the cured film of thephotosensitive resin composition adequately lowers, a better pattern ofthe cured film can be easily formed.

It is also preferred that a weight-average molecular weight of thephotosensitive prepolymer (B) is within a range of 2000 to 250000, andmore preferably 4000 to 100000. In the above range of weight-averagemolecular weight, it is possible to stably obtain a sufficientphotosensitivity of the photosensitive resin composition. In addition,when the weight-average molecular weight is less than 2000, there is apossibility that the surface tackiness of the predried film occurs. Onthe other hand, as the weight-average molecular weight exceeds 250000,there is a tendency of lowering the developing property.

The carboxyl group of the prepolymer (B) may be neutralized by anorganic basic compound such as alkanol amine, alkali-metal hydroxide, oran inorganic basic compound such as ammonia.

As the prepolymer (B), for example, it is possible to use aphotosensitive prepolymer (B 1) obtained by adding an ethylenicallyunsaturated monocarboxylic acid and an unsaturated or saturatedpolybasic acid anhydride to a polyfunctional epoxy compound having atleast two epoxy groups.

As the polyfunctional epoxy compound of the prepolymer (B 1), forexample, it is possible to use a phenol novolac-type epoxy resin, cresolnovolac-type epoxy resin, bisphenol A-type epoxy resin, bisphenolA-novolac-type epoxy resin, bisphenol F-type epoxy resin,N-glycidyl-type epoxy resin, alicyclic-type epoxy resin (e.g.,“EHPE-3150” manufactured by Daicel Chemical Industries, Ltd.), tris(hydroxyphenyl) methane-based polyfunctional epoxy resin (e.g.,“EPPN-502H” manufactured by NIPPON KAYAKU Co., LTD. or “TACTIX-742” and“XD-905” manufactured by DOW CHEMICAL), dicyclopentadiene-phenol-typeepoxy resin, naphthalene-type epoxy resin. As the ethytenicallyunsaturated monocarboxylic acid, for example, it is possible to use(meth)acrylic acid.

As the unsaturated or saturated polybasic acid anhydride of theprepolymer (B1), for example, it is possible to use a dibasic acidanhydride such as succinic anhydride, methyl succinic anhydride, maleicanhydride, citraconic anhydride, glutaric anhydride, itaconic anhydride,phthalic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methyl nadic acid anhydride,hexahydrophthalic anhydride, and methyl hexahydrophthalic anhydride, ora polybasic acid anhydride such as trimellitic acid anhydride,pyromellitic acid anhydride, benzophenone tetracarboxylic anhydride andmethyl cyclohexene tetracarboxylic anhydride.

In addition, as the prepolymer (B), it is possible to use aphotosensitive prepolymer (B2) obtained by a reaction of a compoundhaving a photoreactive ethylenically unsaturated group and a hydroxylgroup in molecule with a copolymer of an unsaturated polybasic acidanhydride such as maleic anhydride and an aromatic hydrocarbon having avinyl group such as styrene or vinyl alkyl ether.

As the compound of the prepolymer (B2), for example, it is possible touse 2-hydroxyethyl(meth)acrylate, 2-hydroxypropyl(meth)acrylate,2-hydroxybutyl(meth)acrylate, diethylene glycol mono(meth)acrylate,dipropylene glycol mono(meth)acrylate, or dibutylene glycolmono(meth)acrylate.

Moreover, as the prepolymer (B), for example, it is possible to use aphotosensitive prepolymer (B3) obtained by a reaction of anethylenically unsaturated compound having a single epoxy group with acopolymer of a first ethylenically unsaturated monomer having nocarboxyl group and a second ethylenically unsaturated monomer having thecarboxyl group.

As the first ethylenically unsaturated monomer, for example, it ispossible to use a straight-chained or branch-chainedalkyl(meth)acrylate, alicyclic(meth)acrylate (an unsaturated bonding maybe included in its ring.), ethylene glycol ester-type (meth)acrylatesuch as hydroxyethyl(meth)acrylate, methoxyethyl(meth)acrylate,propylene glycol-type (meth)acrylate, glycerol mono(meth)acrylate,aromatic-type (meth)acrylate such as benzyl(meth)acrylate,acrylamide-type compound such as (meth)acrylamide,N-methyl(meth)acrylamide, N-propyl(meth)acrylamide anddiacetone(meth)acrylamide, vinyl pyrrolidone, acrylonitrile, vinylacetate, styrene, α-methyl styrene, or vinyl ether.

As the second ethylenically unsaturated monomer, for example, it ispossible to use (meth)acrylic acid, maleic acid, crotonic acid, oritaconic acid.

As the ethylenically unsaturated compound having the single epoxy groupof the prepolymer (B3), for example, it is possible to use aglycidyl(meth)acrylate such as glycidyl(meth)acrylate and2-methylglycidyl(meth)acrylate, or an epoxy cyclohexyl derivative of a(meth)acrylic acid such as (3,4-epoxy cyclohexyl)methyl(meth) acrylate.

As the prepolymer (B), for example, it is also possible to use aphotosensitive prepolymer (B4) obtained by a reaction of a polymer or acopolymer containing an ethylenically unsaturated monomer having anepoxy group as polymerization unit with an unsaturated monocarboxylicacid and a saturated or unsaturated polybasic acid anhydride. Theprepolymer (B4) can be prepared by conventional methods.

As the ethylenically unsaturated monomer having the epoxy group of theprepolymer (B4), for example, it is possible to use the ethylenicallyunsaturated compound having the single epoxy group of the prepolymer(B3).

When using the copolymer containing the ethylenically unsaturatedmonomer, it is possible to use an unsaturated monomer polymerizable withthe ethylenically unsaturated monomer having the epoxy group. Forexample, the first ethylenically unsaturated monomer of the prepolymer(B3) may be used as the unsaturated monomer.

As the unsaturated monocarboxylic acid and the saturated or unsaturatedpolybasic acid anhydride of the prepolymer (B4), for example, it ispossible to use those of the prepolymer (B1).

In addition, as the prepolymer (B), for example, it is possible to use aphotosensitive prepolymer (B5) obtained by a reaction of parts ofcarboxyl groups in a cellulose derivative having carboxyl groups with acompound having an epoxy group and at least one ethylenicallyunsaturated group.

For example, the prepolymer (B5) can be prepared by the followingmethod. That is, the compound having the epoxy group and at least oneethylenically unsaturated group is added to a hydrophilic solventsolution of the cellulose derivative in the presence of a polymerizationinhibitor and a catalyst. The resultant is agitated and mixed to obtaina mixture. The mixture is kept at a reaction temperature of 60 to 150°C., and more preferably 80 to 120° C. to obtain the prepolymer (B5). Asthe polymerization inhibitor, it is possible to use hydroquinone orhydroquinone monomethyl ether. As the catalyst, it is possible to use atertiary amine such as benzyl dimethyl amine and triethyl amine, aquaternary ammonium salt such as trimethyl benzyl ammonium chloride andmethyl triethyl ammonium chloride, or triphenyl stibine.

As the cellulose derivative of the prepolymer (B5), for example, it ispossible to use hydroxypropyl methylcellulose phthalate, hydroxypropylmethylcellulose acetate succinate, cellulose acetate hexahydrophthalate,hydroxypropyl methylcellulose acetate phthalate, or hydroxypropylmethylcellulose hexahydrophthalate.

As the compound having the epoxy group and at least one ethylenicallyunsaturated group of the prepolymer (B5), for example, it is possible touse a glycidyl(meth)acrylate such as glycidyl(meth) acrylate and2-methyl glycidyl(meth)acrylate, or an epoxy cyclohexyl derivative of a(meth)acrylic acid such as (3,4-epoxy cyclohexyl) methyl(meth)acrylate.

By the way, when all of the carboxyl groups in the cellulose derivativereacts with epoxy groups, the prepolymer (B5) of the reaction productbecomes to be insoluble to the diluted alkali aqueous solution.Therefore, an amount used of the compound having the epoxy group and atleast one ethylenically unsaturated group should be determined such thatparts of carboxyl groups of the cellulose derivative remain in theprepolymer (B5).

In addition, as the prepolymer (B), for example, it is possible to use aphotosensitive prepolymer (B6) obtained by a reaction of a compoundhaving a single epoxy group and at least one ethylenically unsaturatedgroup and a saturated or unsaturated polybasic acid anhydride with acellulose derivative having carboxyl groups.

For example, the prepolymer (B6) can be prepared by the followingmethod. That is, a reaction product is obtained by a reaction of all orparts of the carboxyl groups of the cellulose derivative with thecompound having the single epoxy group and at least one ethylenicallyunsaturated group. Then, the saturated or unsaturated polybasic acidanhydride is added to the reaction product to obtain the prepolymer(B6). As a method of preparing the reaction product, it is possible touse the same method explained for the prepolymer (B5). The additionreaction can be performed according to conventional methods.

As the cellulose derivative and the compound having the epoxy group andat least one ethylenically unsaturated group of the prepolymer (B6), forexample, it is possible to use those of the prepolymer (B5). As thesaturated or unsaturated polybasic acid anhydride of the prepolymer(B6), for example, it is possible to use those of the prepolymer (B 1).

As the photopolymerization initiator (C), for example, it is possible touse benzoin, alkyl ether of benzoin such as benzoin methyl ether,benzoin ethyl ether and benzoin isopropyl ether, acetophenone such asacetophenone, 2,2-dimethoxy-2-phenyl acetophenone, 2,2-diethoxy-2-phenylacetophenone, 1,1-dichioro acetophenone, 1-hydroxy cyclohexyl phenylketone, and 4-(2-hydroxyethoxy)phenyl-(2-hydroxy-2-propyl) ketone,anthraquinone such as 2-methyl anthraquinone and 2-amyl anthraquinone,thioxanthone such as 2,4-dimethyl thioxanthone, 2,4-diethy thioxanthone,2-chloro thioxanthone, 2,4-diisopropyl thioxanthone and1-chloro-4-propoxy thioxanthone, ketal such as acetophenone dimethylketal and benzyl dimethyl ketal, xanthone, benzophenone such as3,3-dimethyl-4-methoxy benzophenone, 3,3′,4, 4′-tetra-(tert-butylperoxyl carbonyl) benzophenone and 4-benzoyl-4′-methyl diphenyl sulfido,nitrogen-containing compound such as2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-1-propane-1-on,2benzoyl-2-dimethyl amino-1(4-morpholino phenyl)-butanone-1, and4,-4′-bis-diethyl amino benzophenone, or 2,4,6-trimethyl benzoyldiphenyl phosphine oxide. The photopolymerization initiator can be oneof these materials, or can be a combination of two or more of thesematerials, if necessary.

The photopolymerization initiator (C) may be used together with aconventional photopolymerization enhancer or sensitizer such as abenzoic acid, and a tertiary amine, e.g., p-dimethyl amino benzoic acidethyl ester, p-dimethyl amino benzoic acid isoamyl ester, and 2-dimethylamino ethyl benzoate.

As a first optional component, the photosensitive resin composition ofthe present invention can contain a photopolymerizable ethylenicallyunsaturated monomer (E). As the monomer (E), for example, it is possibleto use trimethylol propane tri(meth)acrylate, pentaerythritoltri(meth)acrylate, pentaerythritol tetra(meth)acrylate,dipentaerythritol penta(meth)acrylate, dipentaerythritolhexa(meth)acrylate, 1,4-butanediol diacrylate, 1,6-hexane dioldi(meth)acrylate, neopentyl glycol di(meth)acrylate, tripropylene glycoldi(meth)acrylate, 2,2-bis[4-((meth)acryloxy ethoxy) phenyl]propane,2,2-bis[4-((meth)acryloxy diethoxy) phenyl]propane,2-hydroxy-1,3-di(meth)acryloxy propane, ethylene glycoldi(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycoldi(meth)acrylate, phenoxy ethyl(meth)acrylate, phenoxy diethyleneglycol(meth)acrylate, methoxy diethylene glycol(meth)acrylate,tetrahydro furfuryl(meth)acrylate, dicyclopentenyl hydroxyethyl(meth)acrylate, 1-methoxy dodecadienyl(meth)acrylate,β-(meth)acryloyl hydroxy ethyl hydrogen phthalate, β-(meth)acryloylhydroxy ethyl hydrogen succinate, 3-chloro-2-hydroxypropyl(meth)acrylate, lauryl(meth)acrylate, cetyl(meth)acrylate,stearyl(meth)acrylate, bisphenol A-diepoxy acrylic acid adduct,(meth)acrylamide, N-methoxy methyl(meth)acrylamide,N,N-dimethyl(meth)acrylamide, (meth)acryloyl morpholine,N-methylol(meth) acrylamide, hydroxy propyl(meth)acrylate, polyethyleneglycol di (meth)acrylate, methylene bis(meth)acrylamide, 2-hydroxy ethyl(meth)acrylate,2,2-bis[4-methacryloyl hydroxy polyethoxy phenyl]propane.The monomer (E) can be one of these materials or can be a combination oftwo or more of these materials, if necessary.

As a second optional component, the photosensitive resin composition ofthe present invention can contain an organic solvent. An amount used ofthe organic solvent should be determined such that the problems inherentin the use of the organic solvent are ignorable. For example, as theorganic solvent, it is possible to use an alcohol such as ethanol,propanol, 2-propanol, butanol, 2-butanol, hexanol, ethylene glycol,diethylene glycol, triethylene glycol, propylene glycol, dipropyleneglycol, butylene glycol, trimethylol propane, neopentyl glycol,glycerin, 1,2,4-butanetriol, 1,2-butanediol, 1,4-butanediol anddiacetone alcohol, ethylene glycol alkyl ether such as ethylene glycolmonomethyl ether, ethylene glycol monoethyl ether and ethylene glycolmonobutyl ether, polyethylene glycol alkyl ether such as diethyleneglycol monomethyl ether, diethylene glycol monocthyl ether andtriethylene glycol monomethyl ether, propylene glycol alkyl ether suchas propylene glycol monomethyl ether, polypropylene glycol alkyl ethersuch as dipropylene glycol monomethyl ether, acetic ester such asethylene glycol monomethyl ether acetate, diethylene glycol monomethylether acetate, propylene glycol monomethyl ether acetate, dipropyleneglycol monomethyl ether acetate, glycerin monoacetate and glycerindiacetate, lactic ester such as lactic ethyl and lactic butyl, dialkylglycol ether such as diethylene glycol diethyl ether, ketone such asmethyl ethyl ketone, cyclohexanone and isophorone, aromatic hydrocarbonsuch as toluene and xylene, oil and aromatic-type mixed solvent such as“SWASOL SERIES” (manufactured by Maruzen Petrochemical Co., Ltd.) and“SOLVESSO SERIES” (manufactured by EXXON CHEMICAL COMPANY), n-hexane,cyclohexane, or tetrahydrofuran. The organic solvent can be one of thesematerials, or can be a combination of two or more of these materials, ifnecessary.

The photosensitive resin composition of the present invention may alsocontain a leveling agent such as a fluorine surface active agent,silicone and a (meth)acrylate copolymer, a thixotropic agent such asAEROSIL, a polymerization inhibitor such as hydroquinone, hydroquinonemonomethyl ether, pyrogallol, tert-butyl catechol and phenothiazine,antihalation agent, flame retardant, plating-resistance improving agent,defoamer, anti-oxidant, pigment wetting agent, organic or inorganicpigment and dye, additives such as synthetic rubber powder and naturalrubber powder, high molecular dispersing agent or surface-active agentfor improving the dispersion stability.

It is preferred to prepare the photosensitive resin composition of thepresent invention according to the following compounding amounts of thewater-soluble photosensitive resin (A), photosensitive prepolymer (B),photopolymerization initiator (C) and water (D).

That is, it is preferred that the compounding amount of thewater-soluble photosensitive resin (A) is 0.1 to 50 wt %, and morepreferably 1 to 30 wt % with respect to the total amount of allcomponents of the photosensitive resin composition except for water (D)and the organic solvent as the second optional component. In the aboverange, there are advantages that (1) the photosensitive resincomposition is excellent in the water-solubility; (2) a cured film ofthe photosensitive resin composition exhibits good water resistance; and(3) a peeling of the cured film is hardly generated at the time of theformation of the cured film. In particular, when the compounding amountis 0.5 to 50 wt %, the photosensitive resin composition can be easilydeveloped with water.

It is preferred that the compounding amount of the photosensitiveprepolymer (B) is 30 wt % or more with respect to the total amount ofall components of the photosensitive resin composition except for water(D) and the organic solvent as the second optional component. In theabove range, there is an advantage that a predried film of thephotosensitive resin composition is almost free from the surfacetackiness.

It is preferred that the compounding amount of the photopolymerizationinitiator (C) is within a range of 0.1 to 20 wt % with respect to thetotal amount of all components of the photosensitive resin compositionexcept for water (D) and the organic solvent as the second optionalcomponent. In the above range, there is an advantage that thephotosensitive resin composition is excellent in the photo-curability.

It is preferred that the compounding amount of water (D) is within arange of 10 to 97 wt % with respect to the total amount of allcomponents of the photosensitive resin composition. In the above range,there is an advantage that the fluidity of the photosensitive resincomposition is suitable to uniformly apply the resin composition onsubstrates. When the photosensitive resin composition contains theethylenically unsaturated monomer (E), it is preferred that thecompounding amount of the monomer (E) is 75 wt % or less with respect tothe total amount of all components of the photosensitive resincomposition except for water (D) and the organic solvent as the secondoptional component. The monomer (E) is useful to more improve thephotoreactivity of the photosensitive resin composition. When thecompounding amount is more than 75 wt %, there is a possibility that thesurface tackiness of the predried film of the photosensitive resincomposition comes into problem.

There is no limitation as to a method of preparing the photosensitiveresin composition of the present invention. For example, the components(A) to (C) and the other optional components may be dissolved,emulsified, and dispersed in water (D) or a mixture of water and anaqueous organic solvent to obtain the photosensitive resin composition.Alternatively, an aqueous solution of the component (A) may be added tothe components (B) and (C) and the other optional components, and thenmixed to obtain the photosensitive resin composition. In these methods,it is preferred to use an agitator or a muller such as homomixer,pipeline homomixer, bead mill, roll mill and ball mill.

Next, a method of forming a required pattern on a substrate with the useof the photosensitive resin composition of the present invention isexplained as an example.

<Applying Step>

First, the photosensitive resin composition can be applied on asubstrate by a dipping method, spray method, spin-coating method, rollmethod. A copper clad laminate used to manufacture printed wiring boardsmay be used as the substrate.

<Predrying Step>

The photosensitive resin composition on the substrate can be dried by ahot-air drying method, electromagnetic induction heating, hot-pressing,or a far-infrared drying method to obtain a predried film.

<Exposing Step>

After a mask having a required pattern such as a phototool artwork isdirectly or indirectly put on the predried film, ultraviolet can beradiated to the predried film through the mask by using a tungsten lamp,chemical lamp, low-pressure mercury lamp, medium-pressure mercury lamp,high-pressure mercury lamp, extra-high-pressure mercury lamp, xenon lampor a metalhalide lamp. Alternatively, it is preferred to adopt a laserpatterning method using a helium-cadmium laser, argon laser or a YAGlaser.

<Developing Step>

After the exposing step, the predried film can be developed with wateror a diluted alkali aqueous solution, so that the non-exposed region ofthe predried film is washed away to leave the exposed region of thepredried film on the substrate as a resist pattern. When developing withthe diluted alkali aqueous solution, it is preferred to use an aqueoussolution of an alkali hydroxide such as sodium hydroxide, potassiumhydroxide and lithium hydroxide, or an alkali carbonate such as sodiumcarbonate and potassium carbonate.

<Etching or Plating Step>

The etching or plating step can be performed to the substrate surfaceexposed through the resist pattern by conventional methods. Whenperforming the etching step, it is preferred to select an etching agentin accordance with a material of a conductive layer of the substrate.For example, an acid etching solution such as copper (II) chloride, oran ammonia etching solution may be used. When performing the platingstep, it is possible to perform a copper plating such as acopper-sulfate plating and a copper pyrophosphate plating, solderplating such as a high throw solder plating, nickel plating such as anickel sulfamate plating, or a gold plating such as a soft gold platingand a hard gold plating.

<Removing Step of Resist Pattern>

When it is required to strip and remove the resist pattern from thesubstrate, the resist pattern can be readily stripped and removed withthe use of sodium periodate or sodium hypochlorite. Alternatively, it ispossible to remove the resist film from the substrate with the use of astronger alkali aqueous solution than the alkali aqueous solution usedat the developing step.

Consequently, the photosensitive resin composition of the presentinvention can provide the following advantages.

(1) Since the photosensitive resin composition does not essentiallycontain the organic solvent, it is possible to prevent the occurrence ofthe problems inherent in the use of the organic solvent.

(2) A predried film of the photosensitive resin composition can bedeveloped with water or a diluted alkali aqueous solution.

(3) A film of the photosensitive resin composition cured by thephotopolymerization reaction is excellent in film hardness, resistanceto etching solution, resistance to plating solution, and thermalresistance. In addition, the cured film has good adhesion with thesubstrate.

(4) The cured film of the photosensitive resin composition can beremoved from the substrate with the use of sodium periodate or anaqueous solution of an alkali-metal hydroxide.

Therefore, the photosensitive resin composition of the present inventionwill be preferably used as a photoresist ink for manufacturing printedwiring boards such as an etching resist ink, plating resist ink, solderresist ink and marking ink, photoresist ink for photogravure,photosensitive composition for manufacturing screen printing stencils,ink for manufacturing color-filter pixels, or an ink for manufacturingcolor-filter protective films.

EXAMPLES AND COMPARATIVE EXAMPLES

The followings are preferred examples of the present invention. However,needless to say, the present invention is not limited to these examples.The units “parts” and “%” used in the examples means “parts by weight”and “wt %”, respectively. In addition, “weight-average molecular weight”was measured by a GPC (Gel Permeation Chromatography) method under thefollowing condition.

[GPC Measuring Condition]

GPC Measuring Apparatus:

SHODEX SYSTEM 11 manufactured by Showa Denko K. K.

Column: SHODEX KF-800P, KF-805, KF-803 and KF-801 in series

Transfer Layer: THF (Tetrahydrofuran)

Flow Rate: 1 ml/min.

Column Temperature: 45° C.

Detector: RI

Conversion: Polystyrene

In the GPC measurement, a THF (tetrahydrofuran) solution having aconcentration of 10 mg/ml with respect to a solid part of each samplewas prepared, and the injection amount is 100 μl.

[Preparation of Photosensitive Resin Aqueous Solution (S-1)]

200 g of a partially-saponified polyvinyl acetate “GOHSENOL GH-17”(manufactured by The Nippon Synthetic Chemical Industry Co., Ltd.,Degree of polymerization: 1700, Degree of saponification: 88 mol %) wasdissolved in 1774 g of water to obtain a first mixture. After 20 g ofN-methyl-4-(p-formyl styryl) pyridinium methosulfate was added to thefirst mixture to obtain a second mixture, 6 g of an 85% phosphoric acidaqueous solution was added to the second mixture to obtain a thirdmixture. The third mixture was kept at 80° C. for 7 hours to obtain thephotosensitive resin aqueous solution (S-1), which corresponds to anaqueous solution of the water-soluble photosensitive resin (A1).

[Preparation of Photosensitive Resin Aqueous Solution (S-2)]

200 g of a partially-saponified polyvinyl acetate “PVA-224”(manufactured by Kuraray Co., Ltd., Degree of polymerization: 2400,Degree of saponification: 88 mol %) was dissolved in 1774 g of water toobtain a first mixture. After 20 g of N-methyl-4-(p-formyl styryl)quinolinium methosulfate was added to the first mixture to obtain asecond mixture, 6 g of an 85% phosphoric acid aqueous solution was addedto the second mixture to obtain a third mixture. The third mixture waskept at 70° C. for 5 hours to obtain the photosensitive resin aqueoussolution (S-2), which corresponds to an aqueous solution of thewater-soluble photosensitive resin (A1).

[Preparation of Photosensitive Resin Aqueous Solution (S-3)]

200 g of a partially-saponified polyvinyl acetate “GOHSENOL GH-17”(manufactured by The Nippon Synthetic Chemical Industry Co., Ltd.,Degree of polymerization: 1700, Degree of saponification: 88 mol %) wasdissolved in 1000 g of water to obtain a first mixture. 40 g ofN-methylol acrylamide was dissolved in the first mixture to obtain asecond mixture, and then 2 g of a 0.1% methoxy hydroquinone aqueoussolution and 3 g of an 85% phosphoric acid aqueous solution were addedto the second mixture to obtain a third mixture. After the third mixturewas kept at 60° C. for 20 hours, the third mixture was neutralized witha 5% caustic soda aqueous solution to obtain a fourth mixture. Water wasalso added to the fourth mixture such that its total weight is 1500 g,to thereby obtain the photosensitive resin aqueous solution (S-3), whichcorresponds to an aqueous solution of the water-soluble photosensitiveresin (A2).

[Preparation of Photosensitive Resin Aqueous Solution (S-4)]

200 g of a partially saponified of a vinyl acetate polymer-unsaturatedcarboxylic acid Na copolymer “KL318” (manufactured by Kuraray Co., Ltd.,Degree of polymerization: 1800, Degree of saponification: 88 mol %) wasdissolved in 1000 g of water to obtain a first mixture. 60 g ofN-methylol acrylamide was dissolved in the first mixture to obtain asecond mixture, and then 2 g of a 0.1% methoxy hydroquinone aqueoussolution and 3 g of an 85% phosphoric acid aqueous solution were addedto the second mixture to obtain a third mixture. After the third mixturewas kept at 80° C. for 5 hours, the third mixture was neutralized with a5% caustic soda aqueous solution to obtain a fourth mixture. Water wasalso added to the fourth mixture such that its total weight is 1625 g toobtain the photosensitive resin aqueous solution (S-4), whichcorresponds to an aqueous solution of the water-soluble photosensitiveresin (A2).

[Preparation of Photosensitive Prepolymer Solution (P-1)]

214 parts of a cresol novolac-type epoxy resin “EPICLON N-680”(manufactured by DAINIPPON INK AND CHEMICALS INCORPORATED, EpoxyEquivalents: 214) was dissolved in 60 parts of methyl ethyl ketone at araised temperature under an airflow to obtain a first mixture. Next, 74parts of acrylic acid, 0.1 parts of hydroquinone, and 2.0 parts ofdimethyl benzylamine were added to the first mixture to obtain a secondmixture. The second mixture was held at 80° C. for 24 hours to obtain athird mixture. After the third mixture was cooled, 136 parts of methylethyl ketone and 76 parts of tetrahydro phthalic anhydride were added tothe third mixture to obtain a fourth mixture. The fourth mixture waskept at 80° C. for 10 hours while being agitated, to obtain a 65%photosensitive prepolymer solution (P-1), which corresponds to asolution of the photosensitive prepolymer (B1). The weight-averagemolecular weight and the acid value of the prepolymer solution (P-1) are12000 and 77 mgKOH/g, respectively.

[Preparation of Photosensitive Prepolymer Solution (P-2)]

150 parts of a styrene-maleic anhydride copolymer “SMA-1000A”(manufactured by ELF ATOCHEM JAPAN, INC.) was dissolved in 149 parts ofmethyl ethyl ketone at a raised temperature under an airflow to obtain afirst mixture. Next, 51 parts of 2-hydroxy ethyl acrylate, 0.1 parts ofhydroquinone, and 3 part of dimethyl benzylamine were added to the firstmixture to obtain a second mixture. After the second mixture was held at80° C. for 12 hours to obtain a third mixture. 22 parts of n-butanol wasadded to the third mixture, and then held for 24 hours to obtain a 60%photosensitive prepolymer solution (P-2), which corresponds to asolution of the photosensitive prepolymer (B2). The weight-averagemolecular weight and the acid value of the prepolymer solution (P-2) are7500 and 156 mgKOH/g, respectively.

[Preparation of photosensitive prepolymer solution (P-3)]

20 parts of methacrylic acid, 80 parts of methyl methacrylate, 100 partsof methyl ethyl ketone, 0.5 parts of lauryl mercaptan and 4 parts ofazobis isobutyronitrile were put in a four-mouth flask, and held at 75°C. for 5 hours at a raised temperature under a nitrogen flow to obtain a50% copolymer solution. The four-mouth flask has a thermometer, glasstube for nitrogen substitution, agitator, and a reflux condenser. Next,15 parts of glycidyl methacrylate, 0.05 parts of hydroquinone and 2.0parts of dimethyl benzylamine were added to the copolymer solution, andheld at 80° C. for 24 hours under an air flow. Then, 13 parts of methylethyl ketone were added to the resultant to obtain a 50% photosensitiveprepolymer solution (P-3), which corresponds to a solution of thephotosensitive prepolymer (B3). The weight-average molecular weight andthe acid value of the prepolymer solution (P-3) are 15000 and 62mgKOH/g, respectively.

[(Preparation of Photosensitive Prepolymer Solution (P-4)]

70 parts of glycidyl methacrylate, 10 parts of methyl methacrylate, 20parts of tert-butyl methacrylate, 100 parts of methyl ethyl ketone, 0.5parts of lauryl mercaptan and 3 parts of azobis isobutyronitrile wereput in a four-mouth flask, and held at 75° C. for 5 hours at a raisedtemperature under a nitrogen flow to obtain a 50% copolymer solution.The four-mouth flask has a thermometer, glass tube for nitrogensubstitution, agitator, and a reflux condenser. Next, 0.05 parts ofhydroquinone, 37 parts of acrylic acid and 2.0 parts of dimethylbenzylamine were added to the copolymer solution, and held at 80° C. for24 hours under an air flow. Then, 38 parts of tetrahydrophthalicanhydride and 73 parts of methyl ethyl ketone were added to theresultant, and held at 80° C. for 10 hours to obtain a 50%photosensitive prepolymer solution (P-4), which corresponds to asolution of the photosensitive prepolymer (B4). The weight-averagemolecular weight and the acid value of the prepolymer solution (P-4) are22000 and 80 mgKOH/g, respectively.

[Preparation of Photosensitive Prepolymer Solution (P-5)]

30 parts of hydroxypropyl methylcellulose acetate succinate “AS-L”(manufactured by Shin-Etsu Chemical Co., Ltd.), 80 parts of methyl ethylketone, 0.05 parts of hydroquinone, 2.6 parts of glycidyl methacrylateand 2.0 parts of dimethyl benzylamine were put in a four-mouth flask,and held at 80° C. for 24 hours. The four-mouth flask has a thermometer,agitator, and a reflux condenser. Next, 8.4 parts of methyl ethyl ketonewere added to the resultant to obtain a 28% photosensitive prepolymersolution (P-5), which corresponds to a solution of the photosensitiveprepolymer (B5). The weight-average molecular weight and the acid valueof the prepolymer solution (P-5) are 63500 and 47.5 mgKOH/g,respectively.

[Preparation of Photosensitive Prepolymer Solution (P-6)]

40 parts of hydroxypropyl methylcellulose acetate succinate “AS-L”(manufactured by Shin-Etsu Chemical Co., Ltd.), 100 parts of methylethyl ketone, 0.05 parts of hydroquinone, 8.7 parts of glycidylmethacrylate and 2.0 parts of dimethyl benzylamine were put in afour-mouth flask, and held at 80° C. for 24 hours. The four-mouth flaskhas a thermometer, agitator, and a reflux condenser. Next, 9.3 parts oftetrahydrophthalic anhydride and 5.7 parts of methyl ethyl ketone wereadded to the resultant, and held at 80° C. for 10 hours to obtain a 35%photosensitive prepolymer solution (P-6), which corresponds to asolution of the photosensitive prepolymer (B6). The weight-averagemolecular weight and the acid value of the prepolymer solution (P-6) are200000 and 59 mgKOH/g, respectively.

[Preparation of Photosensitive Prepolymer Solution (Q-1)]

150 parts of a styrene-maleic anhydride copolymer “SMA-1000A”(manufactured by ELF ATOCHEM JAPAN, INC.) was dissolved in 149 parts ofpropylene glycol monomethyl ether acetate at a raised temperature toobtain a first mixture. Next, 51 parts of 2-hydroxyethyl acrylate, 0.1parts of hydroquinone, and 3.0 parts of dimethyl benzylamine were addedto the first mixture under an air flow, and held at 80° C. for 12 hoursto obtain a second mixture. 22 parts of n-butanol was added to thesecond mixture, and held for 24 hours to obtain a 60% photosensitiveprepolymer solution (Q-1) for Comparative Example 1. The weight-averagemolecular weight and the acid value of the prepolymer solution (Q-1) are7500 and 156 mgKOH/g, respectively.

[Preparation of Photosensitive Prepolymer Solution (Q-2)]

20 parts of methacrylic acid, 80 parts of methyl methacrylate, 100 partsof propylene glycol monomethyl ether acetate, 0.5 parts of laurylmercaptan and 2 parts of azobis dimethyl valeronitrile were put in afour-mouth flask, and held at 110° C. for 5 hours under a nitrogen flowto obtain a 50% copolymer solution. The four-mouth flask has athermometer, glass tube for nitrogen substitution, agitator, and areflux condenser. Next, 15 parts of glycidyl methacrylate, 0.05 parts ofhydroquinone and 2.0 parts of dimethyl benzylamine were added to thecopolymer solution, and held at 80° C. for 24 hours under an air flow.Then, 11 parts of propylene glycol monomethyl ether acetate were addedto the resultant to obtain a 50% photosensitive prepolymer solution(Q-2) for Comparative Example 2. The weight-average molecular weight andthe acid value of the prepolymer solution (Q-2) are 18000 and 62mgKOH/g, respectively.

Examples 1 to 30

Each of the photosensitive resin compositions of Examples 1 to 30 wasprepared according to the following method. That is, a mixture preparedaccording to compounding amounts listed in Tables 1 to 3 wassufficiently agitated by a homomixer, and then heated at 65° C. under anair flow to remove an organic solvent component therefrom, to therebyobtain the photosensitive resin composition of the present invention.

Comparative Examples 1 and 2

Each of photosensitive resin compositions of Comparative Examples 1 and2 was prepared by mixing the photosensitive prepolymer solution (Q-1) or(Q-2) with the other components according to compounding amounts listedin Table 3, while agitating the resultant.

In Tables 1 to 3, trimethylol propane triacrylate (*1) is “ARONIX M-309”manufactured by Toagosei Co., Ltd. The Phenol denatured monofunctionalacrylate (*2) is “ARONIX M-101” manufactured by Toagosei Co., Ltd. Thephotopolymerization initiator (*3) is “Irgacure 907” manufactured byCIBA-GEIGY CORPORATION. The photopolymerization initiator (*4) is“KAYACURE DETX” manufactured by Nippon Kayaku Co., Ltd. The organic dye(*5) is “VICTORIA PURE BLUE BOH” manufactured by Hodogaya Chemical Co.,Ltd.

With respect to Examples 1-30 and Comparative Examples 1 and 2, thefollowing evaluations were performed. Results are shown in Tables 4 to7.

[1] Thickness of Predried Film

The photosensitive resin composition was applied on both surfaces of anFR-4 double-sided copper clad laminate as a substrate by the use of avertical roll coater. The clad laminate has a substrate thickness of 1.6mm and a copper-foil thickness of 35 μm as a conductive layer. After theclad laminate with the photosensitive resin composition was dried at 80°C. for 15 minutes under a hot-air convention, it was cooled at a roomtemperature to obtain predried films on the clad laminate. The thicknessof the predried film was measured.

[2] Surface Tackiness of Predried Film

A pair of phototool artworks having wiring patterns were directly put onthe predried films. The predried films were simultaneously exposedthrough the phototool artworks by the use of an extra-high-pressuremercury lamp such that the accumulated light-amount is 200 mJ/cm². Afterthe exposing step, the surface tackiness of the predried film wasevaluated by removing the phototool artworks from the predried films. InTables 4 to 7, the word “Good” used to show a degree of the surfacetackiness designates that the phototool artwork was easily removed fromthe predried film without contamination of the phototool artwork withthe photosensitive resin composition.

[3] Developing Property

The developing property of the predried film was evaluated under thefollowing conditions (i) and (ii).

(i) After the exposing step, the predried film was developed by sprayinga 1 wt % sodium carbonate aqueous solution thereto at 30° C. at a spraypressure of 1. 5 Kg/cm² for 1 minute, so that the non-exposed portion ofthe predried film was removed.

(ii) After the exposing step, the predried film was developed byspraying water thereto at 30° C. at a spray pressure of 1. 5 Kg/cm² for3 minutes, so that the non-exposed portion of the predried film wasremoved.

In Tables 4 to 7, the symbol “⊚” designates that the non-exposed portionof the predried film was completely removed. The symbol “◯” designatesthat most of the non-exposed portion of the predried film was removed,but a part of the non-exposed portion remained at the boundary betweenthe non-exposed portion and the exposed portion. The symbol “X”designates that the non-exposed portion of the predried film could notbe removed.

[4] Adhesion Test (1)

After the exposing and developing step, the adhesion of a cured film(=the exposed portion of the predried film) of the photosensitive resincomposition was evaluated. The adhesion test was performed according toJapanese Industrial Standard D 0202-1988, 4.15. In this adhesion test,100 square cuts were formed in the cured film to obtain 100 squareblocks, and then an adhesion tape was put on the 100 square blocks ofthe cured film. After the adhesion tape was peeled off from the curedfilm, the number of the remaining blocks of the cured film on thesubstrate was counted. The adhesion of the cured film was evaluated by aratio of the number (N) of the remaining blocks to 100 blocks of thecured film. In Tables 4 to 7, the numeral “1” used to show a degree ofthe adhesion of the cured film designates that the number (N) of theremaining blocks is 100.

[5] Resistance to Etching Solution

The resistance to etching solution means the resistance to an acidaqueous solution of the cured film. After the developing step, anetching treatment of the conductive layer on the substrate with thecured film as a mask was performed with a 40 wt % iron (III) chlorideaqueous solution at 45° C. for 240 seconds to obtain a conductivepattern on the substrate. In Tables 4 to 7, the word “good” used to showa degree of the resistance to etching solution designates that there isno occurrence of peeling of the cured film during the etching treatment

[6] Removing Test of Cured Film

With respect to the Examples 1 to 6, 13 to 18, 25, 27, 29, 30 andComparative Examples 1 and 2, the cured film was stripped and removed byspraying a 3% sodium hydroxide aqueous solution thereto at 45° C. at aspray pressure of 2 kg/ cm². On the other hand, with respect to theExamples 7 to 12, 19 to 24, 26, 28 and Comparative Examples 1 and 2, thecured film was stripped and removed by dipping the cured film in a 3%periodic acid aqueous solution at 20° C. for 2 minutes and spraying theaqueous solution thereto at a spray pressure of 2 kg/cm². To evaluatethe removing easiness of the cured film, time required to completelystrip and remove the cured film was measured, as shown in Tables 4 to 7.In Table 7, the symbol “X” designates that the cured film could not beremoved.

[7] Etching Property

After the cured film was stripped and removed, defects of the conductivepattern such as faults, a decrease in line width, pinhole, and a poorlinearity of pattern were checked. In Tables 4 to 7, the word “good”used to show the etching property designates that there is no occurrenceof such defects of the conductive pattern.

[8] Plating Resistance

After the developing step, the cured film was dipped in a 25 wt %aqueous solution of an agent “PC-455” (manufactured by Meltex Inc.) at30° C. for 5 minutes for the purpose of degrease. Then, the cured filmwas washed with water, and was dipped in a 20 wt % aqueous solution ofan ammonium persulfate-type soft etching agent “NPE-300” (manufacturedby Mitsubishi Gas Chemical Co., Ltd.) at a room temperature for 2minutes. In addition, the cured film was washed with water, and then itwas dipped in a 10 wt % sulfuric acid aqueous solution at a roomtemperature for 1 minute. Next, the cured film was put in a nickelplating bath containing 300 g of nickel sulfate, 40 g of nickelchloride, 40 g of boric acid and 620 g of water, and a nickel platingwas performed at 45° C. at 1.5 A/dm for 10 minutes. After the nickelplating, water washing was performed. Continuously, a gold plating wasperformed in a gold plating bath of “OROBRIGHT HS-2” (manufactured byJAPAN PURE CHEMICAL CO., LTD) at 40° C. at 1.0 A/dm for 10 minutes. InTables 4 to 7, the word “good” used to show a degree of the resistanceto plating solution designates that there is no occurrence of flaking ofthe cured film during the plating procedure.

[9] Adhesion Test (II)

After the plating procedure of the item [8], the cured film was washedby water and then dried. The adhesion of the cured film was evaluatedaccording to Japanese Industrial Standard D 0202-1988, 4.15. The briefexplanation of this adhesion test was already described in the item [4].Results are shown in Tables 4 to 7.

[10] Plating Property

After the plating procedure of the item [8], the cured film was strippedand removed from the substrate by spraying a 3% sodium hydroxide aqueoussolution thereto at 45° C. at a spray pressure of 2 kg/cm². Then, theoccurrence of plating defects was checked by the use of a magnifyingglass. In Tables 4 to 7, the word “good” used to show the platingproperty designates that there is no occurrence of plating defects.

[11] Evaluation of Conductive Pattern

After the cured-film removing step of the item [10], an alkali etchingtreatment was performed. The linearity of a line pattern of the goldplating was checked by the use of an optical microscope. With respect toall of Examples and Comparative Examples, a distance between the top ofa convex portion and the bottom of a concave portion of the gold linepattern is 1 μm or less.

As understood from Tables 4 to 7, the photosensitive resin compositionsof the Comparative Examples 1 and 2 can be developed with a dilutedalkali aqueous solution, but can not be developed with water. On thecontrary, the photosensitive resin compositions of the Examples 1 to 30can be developed with water as well as the diluted alkali aqueoussolution. In addition, the cured film of the photosensitive resincomposition of each of the Comparative Examples 1 and 2 can not bestripped and removed from the substrate with the sodium periodateaqueous solution. However, the photosensitive resin compositions of allof Examples of the present invention can be stripped and removed withthe sodium periodate aqueous solution as well as the alkali aqueoussolution. The other properties of the photosensitive resin compositionsof Examples 1 to 30 are substantially the same as those of theComparative Examples 1 and 2.

In addition, it is confirmed that when the sodium carbonate aqueoussolution is used as the developer, the developing property of thephotosensitive resin composition of each of the Examples 1 to 24, whichcontains trimethyl propane triacrylate or phenol denaturedmonofunctional acrylate as the photopolymerizable ethylenicallyunsaturated monomer (E) is better than that of each of the Examples 25to 30, which does not contain the ethylenically unsaturated monomer (E).

From these results, the photosensitive resin composition of the presentinvention will be preferably used as an etching resist ink, platingresist ink, solder resist ink or a marking ink.

TABLE 1 Examples Unit: parts by weight 1 2 3 4 5 6 7 8 9 10 11Photosensitive resin aqueous solution (S-1) 350 350 350 350 350 350 — —— — — Photosensitive resin aqueous solution (S-2) — — — — — — 350 350350 350 350 Photosensitive resin aqueous solution (S-3) — — — — — — — —— — — Photosensitive resin aqueous solution (S-4) — — — — — — — — — — —65% prepolymer solution (P-1) 370 — — — — — 370 — — — — 60% prepolymersolution (P-2) — 420 — — — — — 420 — — — 50% prepolymer solution (P-3) —— 480 — — — — — 480 — — 50% prepolymer solution (P-4) — — — 480 — — — —— 480 — 28% prepolymer solution (P-5) — — — — 685 — — — — — 685 35%prepolymer solution (P-6) — — — — — 685 — — — — — 60% prepolymersolution (Q-1) — — — — — — — — — — — 50% prepolymer solution (Q-2) — — —— — — — — — — — Trimethylol propane triacrylate (*1) 50 50 50 50 50 5050 50 50 50 50 Phenol denatured monofunctional acrylate (*2) 40 40 40 4040 40 40 40 40 40 40 Photopolymerization initiator (*3) 30 30 30 30 3030 30 30 30 30 30 Photopolymerization initiator (*4) 5 5 5 5 5 5 5 5 5 55 Organic dye (*5) 5 5 5 5 5 5 5 5 5 5 5 Hydroquinone 2 2 2 2 2 2 2 2 22 2 Dicyandiamide 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5

TABLE 2 Examples Unit: parts by weight 12 13 14 15 16 17 18 19 20 21 22Photosensitive resin aqueous solution (S-1) — — — — — — — — — — —Photosensitive resin aqueous solution (S-2) 350 — — — — — — — — — —Photosensitive resin aqueous solution (S-3) 250 250 250 250 250 250 — —— — Photosensitive resin aqueous solution (S-4) — — — — — — — 230 230230 230 65% prepolymer solution (P-1) — 370 — — — — — 370 — — — 60%prepolymer solution (P-2) — — 420 — — — — — 420 — — 50% prepolymersolution (P-3) — — — 480 — — — — — 480 — 50% prepolymer solution (P-4) —— — — 480 — — — — — 480 28% prepolymer solution (P-5) — — — — — 685 — —— — — 35% prepolymer solution (P-6) 685 — — — — 685 — — — — 60%prepolymer solution (Q-1) — — — — — — — — — — — 50% prepolymer solution(Q-2) — — — — — — — — — — — Trimethylol propane triacrylate (*1) 50 5050 50 50 50 50 50 50 50 50 Phenol denatured monofunctional acrylate (*2)40 40 40 40 40 40 40 40 40 40 40 Photopolymerization initiator (*3) 3030 30 30 30 30 30 30 30 30 30 Photopolymerization initiator (*4) 5 5 5 55 5 5 5 5 5 5 Organic dye (*5) 5 5 5 5 5 5 5 5 5 5 5 Hydroquinone 2 2 22 2 2 2 2 2 2 2 Dicyandiamide 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.50.5

TABLE 3 Comparative Examples Examples Unit: parts by weight 23 24 25 2627 28 29 30 1 2 Photosensitive resin aqueous solution (S-1) — — 350 — —— 350 350 — — Photosensitive resin aqueous solution (S-2) — — — 350 — —— — — — Photosensitive resin aqueous solution (S-3) — — — — 250 — — — —— Photosensitive resin aqueous solution (S-4) 230 230 — — — 230 — — — —65% prepolymer solution (P-1) — — 500 — — — — — — 60% prepolymersolution (P-2) — — — 560 — — — — — — 50% prepolymer solution (P-3) — — —— 640 — — — — — 50% prepolymer solution (P-4) — — — — — 640 — — — — 28%prepolymer solution (P-5) 685 — — — — — 900 — — — 35% prepolymersolution (P-6) — 685 — — — — — 900 — — 60% prepolymer solution (Q-1) — —— — — — — — 490 — 50% prepolymer solution (Q-2) — — — — — — — — — 500Trimethylol propane triacrylate (*1) 50 50 — — — — — — 50 50 Phenoldenatured monofunctional acrylate (*2) 40 40 — — — — — — 40 40Photopolymerization initiator (*3) 30 30 30 30 30 30 30 30 30 30Photopolymerization initiator (*4) 5 5 5 5 5 5 5 5 5 5 Organic dye (*5)5 5 5 5 5 5 5 5 5 5 Hydroquinone 2 2 2 2 2 2 2 2 2 2 Dicyandiamide 0.50.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5

TABLE 4 Examples 1 2 3 4 5 6 7 8 Exposing/Developing Step Thickness ofPredried Film (μm)  15  15  15  15  17  17  16  16 Surface Tackiness ofPredried Film Good Good Good Good Good Good Good Good DevelopingProperty (i) ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ (ii) ⊚ ⊚ ⊚ ⊚ ⊚ ◯ ⊚ ⊚ Adhesion Test (I)(N/100) 100 100 100 100 100 100 100 100 Etching Step Resistance toEtching Solution Good Good Good Good Good Good Good Good Removing Testof Cured Film (unit: second) (I)  15  10  17  20  30  25 — — (ii) — — —— — — 140 100 Etching Property Good Good Good Good Good Good Good GoodPlating Step Plating Resistance Good Good Good Good Good Good Good GoodAdhesion Test (II) (N/100) 100 100 100 100 100 100 100 100 PlatingProperty Good Good Good Good Good Good Good Good Evaluation ofConductive Pattern (μm)  ≦1  ≦1  ≦1  ≦1  ≦1  ≦1  ≦1 ≦1

TABLE 5 Examples 9 10 11 12 13 14 15 16 Exposing/Developing StepThickness of Predried Film (μm)  16  16  18  18  15  15  15  15 SurfaceTackiness of Predried Film Good Good Good Good Good Good Good GoodDeveloping Property (i) ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ (ii) ⊚ ⊚ ⊚ ◯ ⊚ ⊚ ⊚ ⊚ AdhesionTest (I) (N/100) 100 100 100 100 100 100 100 100 Etching Step Resistanceto Etching Solution Good Good Good Good Good Good Good Good RemovingTest of Cured Film (unit: second) (i) — — — —  15  10  17  20 (ii) 160180 250 200 — — — — Etching Property Good Good Good Good Good Good GoodGood Plating Step Plating Resistance Good Good Good Good Good Good GoodGood Adhesion Test (II) (N/100) 100 100 100 100 100 100 100 100 PlatingProperty Good Good Good Good Good Good Good Good Evaluation ofConductive Pattern (μm)  ≦1  ≦1  ≦1  ≦1  ≦1  ≦1  ≦1 ≦1

TABLE 6 Examples 17 18 19 20 21 22 23 24 Exposing/Developing StepThickness of Predried Film (μm)  17  17  15  15  15  15  17  17 SurfaceTackiness of Predried Film Good Good Good Good Good Good Good GoodDeveloping Property (i) ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ (ii) ⊚ ◯ ⊚ ⊚ ⊚ ⊚ ⊚ ◯ AdhesionTest (I) (N/100) 100 100 100 100 100 100 100 100 Etching Step Resistanceto Etching Solution Good Good Good Good Good Good Good Good RemovingTest of Cured Film (unit: second) (i)  30  25 — — — — — — (ii) — — 130 90 150 170 230 190 Etching Property Good Good Good Good Good Good GoodGood Plating Step Plating Resistance Good Good Good Good Good Good GoodGood Adhesion Test (II) (N/100) 100 100 100 100 100 100 100 100 PlatingProperty Good Good Good Good Good Good Good Good Evaluation ofConductive Pattern (μm)  ≦1  ≦1  ≦1  ≦1  ≦1  ≦1  ≦1 ≦1

TABLE 7 Comparative Examples Examples 25 26 27 28 29 30 1 2Exposing/Developing Step Thickness of Predried Film (μm)  15  16  15  15 17  17  15  15 Surface Tackiness of Predried Film Good Good Good GoodGood Good Good Good Developing Property (i) ◯ ◯ ◯ ◯ ◯ ◯ ◯ ◯ (ii) ⊚ ⊚ ⊚ ⊚⊚ ◯ X X Adhesion Test (I) (N/100) 100 100 100 100 100 100 100 100Etching Step Resistance to Etching Solution Good Good Good Good GoodGood Good Good Removing Test of Cured Film (unit: second) (i)  15 —  17—  30  25  15  30 (ii) — 100 — 170 — — X X Etching Property Good GoodGood Good Good Good Good Good Plating Step Plating Resistance Good GoodGood Good Good Good Good Good Adhesion Test (II) (N/100) 100 100 100 100100 100 100 100 Plating Property Good Good Good Good Good Good Good GoodEvaluation of Conductive Pattern (μm)  ≦1  ≦1  ≦1  ≦1  ≦1  ≦1  ≦1 ≦1

What is claimed is:
 1. A photosensitive resin composition developablewith a diluted alkali aqueous solution comprising: (A) a water-solublephotosensitive resin selected from the group consisting of a first resinobtained by introducing a styryl pyridinium group into a polyvinylalcohol polymer, a second resin obtained by introducing a styrylquinolinium group into a polyvinyl alcohol polymer, and a third resinobtained by adding N-alkylol (meth) acrylamide to a polyvinyl alcoholpolymer; (B) a photosensitive prepolymer having a carboxyl group and atleast two photopolymerizable ethylenically unsaturated groups in themolecule; (C) a photopylymerization initiator; and (D) water, wherein acompounding amount of said water-soluble photosensitive resin (A) is ina range of 0.1 to 50 weight % with respect to the total amount of allcomponents of said photosensitive resin composition excluding the amountof water, and a compounding amount of said photosensitive polymer (B) isin a range of 30 weight % or more with respect to the total amount ofall components of said photosensitive resin composition excluding theamount of water.
 2. The photosensitive resin as set forth in claim 1,further comprising (E) a photopolymerizable ethylenically-unsaturatedmonomer.
 3. A photoresist ink for manufacturing printed wiring boards,comprising the photosensitive resin composition as set forth in claim 2.4. A predried film obtained by drying the photoresist ink as set forthin claim
 3. 5. A predried film obtained by drying the photosensitiveresin composition as set forth in claim
 2. 6. A photoresist ink formanufacturing printed wiring board, comprising the photosensitive resincomposition as set forth in claim
 1. 7. A predried film obtained bydrying the photoresist ink as set forth in claim
 6. 8. A predried filmobtained by drying the photosensitive resin composition as set forth inclaim
 1. 9. The photosensitive resin composition as set forth in claim1, wherein an acid value of said photosensitive prepolymer (B) is withina range of 20 to 300 mgKOH/g.